Tracer bullet: It leaves a visible mark or 'trace' while in flight, so that the path of bullet can be seen . Dum - dum bullet: The nose of the bullet is not covered by jacket & exposed. It expands or mushrooms on striking the target, producing a large hole & more damage. Incendiary bullets: Incendiary bullets contain phosphorus. Type of army bullet used to cause fire in the target. Tandem bullet: Bullets ejected one after the other, when the first bullet having been struck in the barrel fails to leave the barrel and is ejected by a subsequently fired bullet.